Automatic change-over device



Dec. 6, 1938. R. wfTl-lomAs ET L 2,138,989 AUTOMATIC CHANGE-OVER DEVICEFiled sa py 1957 \JZWQWM Q r I INVENTOR.

'ROSSWELL w. THOMAS CHARLES MAC SPORRAN BY, k MAMu, Q

A TTORNEYS.

Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE MacSporran,

Detroit,

Mich assignors to Phillips Petroleum Company, a corporation of DelawareApplication September 14, 1937, Serial No. 163,842

6 Claims.

The present invention relates to improvements in devices forautomatically changing withdrawal connections from one source of highpressure gas to another upon decrease in pressure in the first source.

The usual two drum system for bottled gas distribution comprises a pairof cylinders containing liquefied gas, and a service line to the gasconsuming appliance connected through a pressure reducing regulator toboth the cylinders. Some means is provided for having one -or both ofthe cylinders turned on at one time in order to supply gas to theregulator and service line and it is necessary to be able to disconnectand replace either cylinder without loss of gas and preferably withouttoo much manipulation of valves or other mechanism. Prior practice hasbeen to open the valve on the active cylinder while keeping the valve onthe reserve cylinder closed. When the gas in the active cylinder becameexhausted the valve on that cylinder was closed and the valve on thereserve cylinder opened. This series of steps was necessary to preventthe high pressure gas in the reserve cylinder from feeding into theexhausted cylinder. The result was that there was a cessation of the gassupply to the gas consuming appliances and all pilot lights wereextinguished. Further in order to remove and replace the exhaustedcylinder with a new reserve cylinder, it was necessary to close thevalve in the active cylinder in order to prevent escape of its gas intothe atmosphere again resulting in a cessation of. the gas supply to theappliances.

To rectify this situation automatic change-over devices were developedsuch as those shown in U. S. Patents Nos. 1,960,466, issued toWalter I.Thrall, and 2,047,338, issued to one of the present inventors, but thesedevices are complex and expensive.

The present device is a simple and inexpensive means of automaticallyaccomplishing the change-over from an exhausted cylinder to the reservecylinder without cutting off the supply of gas to the appliances.

An important object of the invention is to provide a simple inexpensivechange-over device.

An additional important object is to provide a change-over device whichwill operate on a predetermined pressure differential between the twoThis invention is an improvement over that disclosed in applicationSerial No. 163,841 filed September 14, 1937, with Rosswell W. Thomas asinventor.

In the drawing forming a part this specification, and in which likenumerals are employed to designate like parts throughout the same,

Fig. 1 is a view in elevation showing a system embodying the presentinvention,

Fig. 2 is a sectional view of .the manifold,

Fig. 3 is a view partly in elevation and partly in cross section of themanifold in the neighborhood of the diaphragm assembly, and

Fig. 4 is a sectional view of. the diaphragm assembly with part of thespool broken away.

Referring to Fig. l of the drawing, reference numerals, 6, 6 indicatecylinders for containing the liquefied gas. Valves 1, I normally closethese containers and have couplings 8, 8' for connection to withdrawalpipes 9, 9. Pipes 9, 9' terminate in a manifold it which in turn isconnected to a consumer service or supply line H. Interposed in line llis a regulator 12 for controlling the pressure of the gas to be fed tothe appliances at the other end of the service line. It will be evidentfrom further description that pipe 9, manifold Ill and pipe 9' togetherconstitute a conduit connecting the two cylinders 6, 6 and that serviceline .II is taken off this conduit at manifold 10. With the aboveconnections completed, valves I, .7 can be opened. Then service line II, depending upon the position of the valves in manifold l0 as laterdescribed,

will draw gas from either of the cylinders 6, 6.

Referring to Fig. 2 which shows an enlarged sectional view of manifold10, reference numeral l3 designates a modified pipe elbow havingthreaded pipe coulings l4, l5. Screw threaded into elbow I3 is a fittingl6 having a threaded pipe coupling l1. Pipe couplings l4 and I! openinto a chamber l8, formed by elbow l3and fitting l6, through orifices l9and 20 respectively, while coupling l5 opens into the chamber throughbore 2| and groove 22. Valve seats 23 and 24 are formed around theperiphery of orifices l9 and 20 on the chamber side. A pair of valvesleeves 25, 26 are slidably mounted in chamber I 8, the valve sleevesbeing hexagonal in cross section to allow flow of gas past them. Eachvalve sleeve 25, 26 is further formed with a valve face to co-act withvalve faces 23, 24 in the form of resilient disks 25', 26'. Chamber I8is enlarged at 21 to receive a diaphragm assembly comprising a spool 28which acts as a guide for a slidable hollow connector 29. A pair ofdiaphragms 30, 3|

is thus evident that this assembly divides chamher l8 into three parts,the middle part being hermetically sealed from the other two which arein communication with each other through hollow connector 29. A pair ofsprings 34, 35 are positioned in chamber 18 between the connector andthe valve sleeves 25, 28. In the rear of elbow I3 is a screw threadedopening 38 through which passes a spindle 31 held in place by a gland38. The inner end of spindle 31 passes through spool 28 and terminatesadjacent connector 29. At this point the inner portion of spool 28 iscut away to expose connector 29 and the connector is slotted at 39 toreceive an eccentric 40. On the exterior end of spindle 31 is positioneda lever 41 fixed with respect to thespindle by nut 42.

The springs are so designed that with the connector in the positionshown in Fig. 2 each spring presses with equal force on its valvesleeve. Thus with containers 6, 8' full of liquefied gas and valves 1, Iin open position, gas will feed equally from each container into serviceline II. This usually is not desirable since both containers will becomeexhausted at about the same time. In normal operation, considering thatit is desirable to draw gas from, container 6 while maintainingcontainer 6' in reserve, the lever 4| is turned clockwise throughdegrees thereby through eccentric 48, moving connector 29 to the rightand compressing spring 35 while relieving pressure on spring 34. Theparts are so designed that the bias on spring 35 will be, for example,such that an eleven-pound pressure drop will occur across valve 28 whilethe bias on spring 34 will result in a one-pound pressure drop acrossvalve 25. Assuming that the pressure in each container is one hundredpounds, it will be apparent that the pressure in chamber I8 will beninety-nine pounds due to the onepound pressure drop across valve 25.Since this leaves only one pound difierence in pressure acting uponvalve face 26', this valve will remain closed because eleven poundsdifference in pressure is necessary to open it. When container 5approaches depletion the pressure in chamber l8 will begin to drop. Whenthe pressure has dropped to eighty-nine pounds, valve 25 will open. Thedecreasing pressure in container 8 will allow valve 25 to close. At thecustomer's convenience container 6 can then be replaced by a fullconainer. If valve I is now opened it will be seen that valve 25 willopen and valve 28 close since the same conditions are present asoriginally, namely one hundred pounds pressure in both containers. Thisis highly undesirable because the customer will have no way of I tellinghow much gas remains in container 5'. The ideal situation would be tohave the new container 6 as a reserve container to be connect- 1vention, herewith shown and described is to be taken as a preferredexample of the same and that various changes in the shape, size andarrangement of parts may be resorted to without departing from thespirit of this invention and further that the theories of operation setout, although believed to be accurate are not to be considered as thesole basis of the operativeness of this device but that this device doesoperate successfully whether or not upon the principles describedherein,this invention to be limited solely by the appended claims.

We claim:

In a system for storing and utilizing high pressure fuel gas, thecombination comprising a pair of containers for said gas, a conduitconnecting said containers together, a consumers service line connectedto said conduit, a pair of valves in said conduit, one on each side ofsaid service line, each said valve being biased to close said conduitagainst pressure in each said container, said valves openable bypressure in said containers, and means for varying the bias on each saidvalve so that whichever one said valve desired will present a greaterresistance to gas flow than the other.

In a system for storing and utilizing high pressure fuel gas, thecombination comprising a pair of containers for said gas, a conduitconnecting said containers together, a consumers service line connectedto said conduit, a pair of valves in said conduit, one on each side ofsaid service line, each said valve being biased to close said conduitagainst pressure in each said container, said valves openable bypressure in said containers, and a movable member operable from theexterior of said conduit for varying the bias on each said valve so thatwhichever one said valve desired will open before the other.

3. In a system for storing and utilizing high pressure fuel gas, thecombination comprising a pair of containers for said gas, a conduitconnecting said containers together, a consumer's service line connectedto said conduit at a point intermediate said containers, a pair ofvalves in said conduit onev on each side of said point, a spring actingupon each said valve for biasing said valve closed against pressure insaid container, said springs being separated from one another by amovable member, and means exterior of said conduit for actuating saidmovable member to vary the relative bias on said valves.

4. A manifold for use in high pressure fuel gas systems wherein a pairof containers for said gas are connected to a consumer's service line,comprising a body portion having a chamber with a pair of gas inlets forconnection with said containers and a gas outlet for connection withsaid service line, a pair of valves for closing said inlets systemswherein a pair of containers for said gases are connected to a consumersservice line, comprising a body portion having a chamber with a pair ofgas inlets for connection with said containers and a gas outlet forconnection with said service line, a pair of valves for closing saidinlets against pressure in said containers, a movable member in saidchamber intermediate said valves, spring means in said chamber biasingsaid valves into closing position, said movable member having co-actionwith said spring means where-' a a,1ss,ase by the bias on each saidvalve can be varied rela- ,azainst pressure in said containers, amovable tive to the other.

8; A manifold for use in high pressure iuelsas member in said chambefbetween said valves, a spring between each valve and said projectingmember for biasing said valves into closed position, and means exteriorof said manifold for actuating said movable member, whereby the relativebiasing action 'of .said springs can be varied.

ROSSWELL W. THOMAS.

CHARLES MACSPORRAN.

